Kp Rating

[Laurend818]

I am just curious as I have noticed that a lot of "run-aways" and also switching back and forth between GPS and ATI mode seems to happen on days with a high Kp rating.

Is there anyone else that have noticed this as well?

For those that don't know what a Kp rating is, it is the amount of solar activity that could cause issues with GPS signals. As a rule I don't fly on days with a Kp rating of 5 or higher and have not had any issues.

Just my observation.

Fly on

 

[msinger]

The Kp rating is not known to have any negative effects on Phantoms. You can safely ignore it.

 

[Laurend818]

Thanks for your quick response msinger.
For my own curiosity, what is the threshold for number of satellites for which the Phantoms switch from GPS to Atti mode?

 

[Numone]

Thanks for your quick response msinger.
For my own curiosity, what is the threshold for number of satellites for which the Phantoms switch from GPS to Atti mode?

Nice question!

 

[Meta4]

Thanks for your quick response msinger.
For my own curiosity, what is the threshold for number of satellites for which the Phantoms switch from GPS to Atti mode?

It's not a simple answer.
If you have a P3 Adv or Pro, it uses two different satellite systems - GPS (US) and Glonass (Russian)
It needs 6 sats of one type to get a good fix.
When you see that your Phantom has acquired 15 sats, there's no indication of how many of each type but you would have at least 6 of one type.
If you have lower numbers - say 9, that could be 4+5 which would leave you in atti or it could be 7+2 which would have you in P-GPS.
WHen your Phantom is up in the sky with a good sky view, you should have access to many more sats and have no problem finding the right number.
It's only going to be an issue down low where obstacles block some of the sky and reduce the number of sats your Phantom can see.

The answer for Standard owners is simple as it only receives US GPS sats.
For them the answer is 6.

 

[Numone]

It's not a simple answer.
If you have a P3 Adv or Pro, it uses two different satellite systems - GPS (US) and Glonass (Russian)
It needs 6 sats of one type to get a good fix.
When you see that your Phantom has acquired 15 sats, there's no indication of how many of each type but you would have at least 6 of one type.
If you have lower numbers - say 9, that could be 4+5 which would leave you in atti or it could be 7+2 which would have you in P-GPS.
WHen your Phantom is up in the sky with a good sky view, you should have access to many more sats and have no problem finding the right number.
It's only going to be an issue down low where obstacles block some of the sky and reduce the number of sats your Phantom can see.

The answer for Standard owners is simple as it only receives US GPS sats.
For them the answer is 6.

Cheers Meta4

 

[msinger]

It's far more common for the Phantom to switch into ATTI mode due to bad/unusable compass data. I only recall seeing a handful of logs where the GPS count was low enough to cause an auto switch to ATTI mode.

 

[FunN4lo]

The Kp rating is not known to have any negative effects on Phantoms. You can safely ignore it.

It's far more common for the Phantom to switch into ATTI mode due to bad/unusable compass data. I only recall seeing a handful of logs where the GPS count was low enough to cause an auto switch to ATTI mode.

msinger I think you are one of the most knowledgeable guys here. I have used your advice many times and your Phantom Help pages are phenomenal. I don't think all of the kp index warnings are at the red alert level, every time some of the apps out there tell you that they are. But these storms do effect GPS. The Phantom can not be immune. The best description of the effect I have found is from one of NOAA's pages. (the signal bends through the ionosphere) causing wild position fluctuations. It is interesting to note different things occur close to the equator, than do at higher latitudes.

The Phantoms spacial location is GPS augmented by the compass (direction) and speed. I wonder how many of those compass errors that you see, are actually an algorithm weighting bad gps info as accurate, therefore determining the compass info can not be accurate?

 

[Meta4]

But these storms do effect GPS. The Phantom can not be immune. The best description of the effect I have found is from one of NOAA's pages. (the signal bends through the ionosphere) causing wild position fluctuations.

There's a big difference between can affect GPS and will affect your flying.
GPS is not pinpoint accurate anyway and commonly has an error of +/- 1-2 metres and sometimes a little more.
At KP 6 there would be no noticeable effect on the GPS of a Phantom.
At higher KP values the offset may be more but at KP 6 your GPS position may be off by 2-3 metres.
See http://www.nstb.tc.faa.gov/reports/PAN86_0714.pdf and look at P31-32.
Your Phantom would still fly properly but RTH may be off by a couple of metres ... but GPS accuracy is variable anyway so you'd never notice.
It won't cause the Phantom to go crazy or do unpredictable things.

By the time the K index is at a level that causes real drone flying problems, your Phantom would be the last of your concerns.

I wonder how many of those compass errors that you see, are actually an algorithm weighting bad gps info as accurate, therefore determining the compass info can not be accurate?

Probably none. DJI have programmed the flight controller to work with realistic values.
Bad GPS info is very, very rare.
When we see compass errors reported, the reason is usually pretty clear - and the most common cause is bad compass calibration by the user.

 

[Laurend818]

Thanks Fun4... my original intention of this post was not to do anything other than make people aware that these Kp ratings DO effect gps accuracy. I have read the NOAA papers that Fun4 mentioned. I did this a long time ago and that is the reason for the original post. Will this totally disable your drone,,NO. but during times of high Kp rating be aware of reduced GPS accuracy.

This could effect things like RTH.. it may be off slightly from what you expect. Should not be effected greatly but a small amount. During times of EXTREME Kp ratings (very rare) you may not get a GPS lock but would get ATTI mode without a problem.

No red flags,, just a caution for someone doing any kind of precision gps flying.


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[msinger]

If you have some studies showing the Kp ratings DO effect Phantoms specifically, then please go ahead and share that information. Otherwise, we can safely cross this worry off the list. People don't need to worry about something else that'll never happen

 

[Laurend818]

If you have some studies showing the Kp ratings DO effect Phantoms specifically, then please go ahead and share that information. Otherwise, we can safely cross this worry off the list. People don't need to worry about something else that'll never happen

Although I may not totally agree with you, I will not escalate this into something more than the original intent. The NOAA, papers are there to read, do the effect Phantoms specifically NO. They however effect ANYTHING that uses GPS.

Case closed from my end. No further discussion from me.


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[msinger]

Case closed from my end. No further discussion from me.

There are other threads like this one and they all end exactly like this. The OP's are never able to produce evidence that this is an actual problem that affects Phantoms. I do enjoy discussing all things Phantom, but I also like sharing information that is both factual and proven.

 

[Meta4]

They however effect ANYTHING that uses GPS.
Case closed from my end. No further discussion from me.

Did you see post #9 above?
Rather than saying it CAN affect GPS, you have to look at HOW MUCH it might affect GPS.

 

[Laurend818]

Did you see post #9 above?
Rather than saying it CAN affect GPS, you have to look at HOW MUCH it might affect GPS.

Did not show up in my update..thanks..was going to post the NOAA paper,,but will not bother. That reply just covers exactly what I was trying to say. Maybe what I was trying to say was received wrong.


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[FunN4lo]

There's a big difference between can affect GPS and will affect your flying.
GPS is not pinpoint accurate anyway and commonly has an error of +/- 1-2 metres and sometimes a little more.
At KP 6 there would be no noticeable effect on the GPS of a Phantom.
At higher KP values the offset may be more but at KP 6 your GPS position may be off by 2-3 metres.
See http://www.nstb.tc.faa.gov/reports/PAN86_0714.pdf and look at P31-32.

Thats a report for 3 months of 2014 in Boulder, Co.?!?!?

Geomagnetic storms ebb and flow just like weather, and effect different parts of the planet/country at different times

 

[FunN4lo]

If you have some studies showing the Kp ratings DO effect Phantoms specifically, then please go ahead and share that information. Otherwise, we can safely cross this worry off the list. People don't need to worry about something else that'll never happen

If you have some studies showing the Kp ratings DO NOT effect Phantoms specifically, then please go ahead and share that information.

 

[msinger]

If you have some studies showing the Kp ratings DO NOT effect Phantoms specifically, then please go ahead and share that information.

So, you think it would be a wise use of time to prove that something that has never been a problem is still not a problem? That sounds like a colossal waste of time to me.

 

[Meta4]

If you have some studies showing the Kp ratings DO NOT effect Phantoms specifically, then please go ahead and share that information.

IF Kp caused issues for flyers, it would affect lots of flyers, not just 1 or 2.
In three years I've seen lots of warnings that flying may be risky because of solar activity and high Kp levels.
I've seen lots of people suggest that MAYBE Kp index was to blame for all kinds of issues - but all were explained by quite normal things.
I still haven't seen any cases where there was any noticeable influence on Phantom flying at any Kp index level during that time.
And as I explained in post #9 above you won't notice anything either because if there was an influence, it would be indistinguishable from the normal variation in consumer GPS precision.
It's not going to send your Phantom away or make it fall from the sky.

 

[FunN4lo]

Deep breaths. I said in post #8 that I don't believe all of the red zones in the kp apps. I am not a rocket scientist. But rocket scientists say ion storms effect gps reception, and the Phantom has a gps receiver.

Do high kp indexes make Phantoms fly away or crash? As we have established, there is no scientific study one way or the other. So, my only frame of reference is what the rocket scientists say

For me, I give a high kp index at lest a little weight in my pre-flight safety decision process. For instance, combined with other negative conditions, i.e. higher wind, I have made the no-fly decision, when the wind level alone might not have stopped me. Or, I have decided not to fly BVLOS during high kp indexes.

I have never crashed during higher kp indexes when I have made the decision to fly. I have never crashed when made the decision not to fly, in other higher kp index times. My pre-flight safety decision process is currently working well for me.